Variable tread vehicle



Oct. 29, 1946. T. o. DAVIDSON ETA 2,410,271

VARIABLE TREAD VEHICLE Filed Feb. 1. 1945 INVENTORS AYTORNEYJ Patented Oct. 29, l946 rence B. Schaiier, Los Angele's'jcalifg assignors Q I to Bucyrus-Erie Company," South Milwaukee,

' Wis., a corporation of Delaware" Application February 1, 1945 SerialNo. 575,660

Our invention relates to new .and useful improvements invariable tread vehicles, more particularly such vehicles for the purpose. of carrying trench excavators of the Ruth ty'pe, so-called', suchfor exampleas shown and described in U. S. PatentNo. 1,877,556, issued September 13, 1932, to Ary C. Clark et al., for improvements in Canal excavators. I V I .Such machines consist .ofa main frame, usually with creeping traction mounting, and carrying the engine and excavating machinery; and

5 Claims. (01. 1 80- 91) and useful details, which will be readily evident as the description progresses,

Our invention consists. in the novel parts and in the combination and arrangement thereof, whichar defined in the appended claims, and of which one embodiment is exemplified in the accom'pa nying] drawing, which is hereinafter particularlydescribed and explained.

an auxiliary frame, also usually mounted on creeping traction, and located on the outer end of an extensible outrigger, usually telescoping. I The object of thisextensibility' of the outrigger is'so fthat the distanc'ebetween the two creeping tractions can be adjusted so as to span the ch'aniiel which is being dugfor cleaned. In. the improved models of such a machine, the outrigger'traction mechanism, as well as the main traction mechanism, is self-propelled- With such a machine, the easiest way to run the outrigger in and out, is by turning the outrigger unit at an angle, so'thatit will run' in or out under its own power as the machine progresses along the ditch. Such ,is the case with. the machine shown and described in the'plark. patent, above referred to, and with the. machine shown and described in 11.5. Re. Patent No. 21,106, issued May 30, 1939,

V to Lawrence 'B. Schau'er (one of the presentpat ente'es) for improvements in variable tread vehic'les.

, However, in the device of each ofthe above mentioned twopatentsthe turning of the outrigger has tobe accomplished by hand by rotatng a hand wheel or crank. Furthermore this hand steering has been found to be at the, best very laborious, and. at the worst practically impossible, depending on the condition of the ground on which the outriggeru nit is resting. In some instances, the steering can be effected only by having one man walk alongside manipulating the f Throughout the description, thesame reference number is applied to the same member orv to similar members.v

Figure 1 is a front elevation of a trench excavator embodying our invention. For simplification, all machinery, other than that involvedin our invention, has been eliminated. I Figurez isa plan view of the same.

Figure 3 is the same as Figure 2, exceptthat in Figurefibur outrigger unit has been turned.

Referring now to all these figures, we see that It is the main-frame of a trench excavator, sup-' ported on .creeping.traction mechanism l2, driven in any convenient manner by a main engine (not shown). W f1:

Across the ditch l3 from the main frame ll, there is an outrigger frame l4, connected to the mainframe H by afltelescoping', beam l5, which may be of'anyco'nvenient construction inasmuch asthe details thereof constitute no part of our invention. T I v The outrigger frame I4' is connected to the telescoping beam [5, by a single pivot-pin [6", which must' be definitely to one side of the centerline of the creeping traction mechanism I'I- which supports the outrigger frame. The mainengine, referred' toearlier herein, isiequipped with ap propriate clutchesand brakes and other mech'- anism (notshown'), to control the relative speed i of the two tract'ion mechanisms t2 and l'l.

f On the" deck of outriggerframe' M, on the side oppositefrom' pivot l6, thereare a series of holes l8, arranged in a'cir'cular are about pivot l6 'as V a center; Beam 'l5extends through outrigger steering wheel or handle, while another manruiis. L

themachine'; but this expedient is manifestly impossible with one-man operation.

Of course, the turning could be eifected by power, but this would .requirethe additional eX-. pense. of much additional machinery. Infact, evenfthe hand-power turning apparatus involves some additional expense.

Accordingly the principal object of our invention is to provide an inexpensive means for steering't'he. outrigger creeping traction unit without the use of either a hand-power steer or'a power steer.

In addition, to our principal object, above statediwefhave 'workediouti a number of novel frame lta'n'd has ahole' Is the same radial distaiice-from pivot l6 as areholes l8. Below each of'lioles 18" and below the level of hole I9, there" is a second series of registering holes 20. g

, Pivot It need not necessarily be on either side of outrigger frame I'4','rath er than the other, nor

nfeedh'oles' l8, l9'and 2|] be on the opposite side, provided only that holes I8, 19 and 20 are suifi} ciently' spaced from pivot I-Gto assure a firm non-} pivoting attachment of outrigger frame I4 to beam l5; Y

' ,creeping traction mechanism l1 pivotally'sup ports-outrigger frame [4- through "a combined drive shaft and pivot 21'. This-"shaftis' driven sprocket'22, which in-turn is driven by sprockl' 3 'et-chain 23, which in turn is driven by sprocket 24, which in turn is driven by shaft 25, which in turn is driven by universal coupling 26, which in turn is driven by shaft 21.

Shaft 25 is supported by outrigger frame l4 in any convenient manner. As shown, it is supported by bearing-bracket 28.

Shaft 21 is supported by telescoping beam [5 in any convenient manner. As shown, it is supported by bearing-bracket 29. p

Unless some alternative expedient be employed, it is essential that universal coupling 26 bealmost exactly vertically aligned with pivot 16, and that shaft 21 be substantially in the same vertical plane as telescoping beam l5, although not necessarily above it.

For that matter, the whole mechanism for conveying power from the main frame tothe outrigger frame could beelirninated, and some other and more direct means of driving creeping traction I! could be'employed, for example as shown infthe Clark patent cited earlier herein, or it need not be driven at all, although preferably it should. Other forms of traction than creeping could likewise be employed. In the claims, when we refer to traction support we mean a mechanism having ground-engaging load-supporting groundtraversing potentialities, but not, necessarily implying capability for tractive effort, unless this is specifically'called for by any given claim.

Ourmethod of driving shaft 2! is as follows, although any other telescoping means could be employed. Gear 30is journaled in bracket 3|. The right hand end' of shaft 21 is squared or otherwise keyed'to fit slidably in the hub of gear 30. Gear 30 is then driven, in any convenient manner, by the main engine (not shown). Normally outrigger frame [4 is locked (by pin 32, passing through hole E9, the central one of holes l8, and the corresponding one of holes 20, as, in Figures 1 and 2) against pivoting with respect to beam l5. p

When .the operator desires to extend or contract beam l5, he removes pin l9. Avery slight forward or backward propulsion of the machine will swing the outrigger frame (as, for example, shown to the pivot as a center, whereby the outrigger frame may be locked in various selective angular relations with respect to the beam, to permit the outrigger frame to be steered by unlocking the outrigger frame, then driving the main frame, and then locking the outrigger frame in its new angular position, the outrigger frame thus locked in new angular. position serving to'expand or contract the telescoping beam as the vehicle progresses.

2. A variable tread vehicle, according to claim 1, further characterized by the fact that the driving means for the main traction is located on the main frame, and has a driving connection with the outrigger traction, which driving connection comprises: a telescoping drive shaft in substantially the same vertical plane as the beam; a drive shaft on the outrigger frame; and a universal coupling between the two shafts, which coupling is located in substantial vertical alignment with the vertical pivot.

3. A variable tread vehicle, according to claim 1, further characterized by the fact that the selective lockin means are arranged in a circular arc about the vertical pivot as a center.

4. A variable tread vehicle, according to claim 1, further characterized by the fact that the selective locking means comprise a substantially vertical hole in the beam, and a series of substantially vertical holes in the outrigger frame, all arranged in a circular are about the vertical pivot as a center, and a pin for passing through the former hole and one of the latter holes when in register.

5. In a machine of the class described: a freely laterally extensible frame; means for supporting and propelling one side of the frame; similar means at the opposite lateral side of the frame;

' the latter means being shiftable laterally with the in Figure 3), due to the oifset locationof pivot I6. Pin .32 can then be reinserted, thus locking the outrigger frame in its swung position.

Further propulsion of the machine in the ap:

propriate direction will then extend or contract laterally extensible portion of the frame, and shiftable about a vertical axis angularly with respect' to the longitudinal axis of the frame and the first propelling means; said frame being capa ble of being extended and contracted when said frame is propelled while the latter means is positioned, angularly with respect to the frame; said vertical axisbeing offset from the center line of the second supporting means; and'means for lockingthe second supporting means in angular beam l5, whereupon outriggerframe H can be 7 restored to parallelism withmain frame H, by a repetition of the maneuver first described.

If desired, means'may be provided for locking beam l5 against further extension or contraction; but such means are not shown, as theydo not constitute a part of our'invention. f

Having now described and illustrated one form of 'our invention, we wishit to be understood that our invention is not .to be limited to the specific form or arrangement of parts herein described rigger frame; and a series of selective locking means spaced radially from the vertical pivot and spaced from each other angularly with respect relation to the extensible frame; whereby the second supporting means may be steered by unlocking it, then driving the first supporting means, and" then looking the second supporting means in its new'agnular position, the second supporting means thus locked in new angular position serving to expand'or contract the laterally extensible portion as the vehicle progresses.

6. In a variable tread vehicle, having a main frame and an outboardtraction support, and a laterally adjustable connecting means between the main frame and the outboard support; means providing a vertical axis offset from the centerline of the outboard support, about which said outboard support can be angularly adjusted with respect to'the connecting means; and means for selectively locking said outboard support in a plurality of angularly adjusted positions; whereby the outboard support may be steered by unlocking it, then driving the outboard support, and then looking the outboard support in its new angular position, the outboard support thus serving to expand or contract the laterally adjustable connecting means as the vehicle progresses.

i TREVORO. DAVIDSON.

LAWRENCE B. SCHAUER. 

